Nature: Carbicrete

Chemist Zoey Herm fills a balloon with carbon dioxide using a bike-tyre cartridge, then fits it over the lip of a bottle of chalky white pellets. While she chats with fellow chemist Thomas McDonald, co-founder and chief executive of start-up Mosaic Materials, the bottle becomes warm to the touch, releasing heat as the porous materials inside absorb the CO2.

A time-lapse video of the demo is striking: in 20 minutes the balloon completely deflates as the gas is absorbed by the pellets. These materials absorb more CO2, and release it more readily, than existing CO2 separation materials. McDonald and Herm hope that the technology can lower the cost of carbon-capture systems for fossil-fuel power plants.